SQL - CURD 示例

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  1 创建数据库
  2 CREATE DATABASE guyu;
  3
  4
  5 进入数据库
  6 USE guyu;
  7
  8
  9 创建表格名:emp
 10 CREATE TABLE emp (
 11     empno INT PRIMARY KEY auto_increment,
 12     ename VARCHAR (20),
 13     job VARCHAR (30),
 14     salary NUMERIC (7, 2),
 15     bonus NUMERIC (7, 2),
 16     mgr INT,
 17     hiredate date,
 18     deptno INT
 19 );
 20
 21
 22 --查询该表字段信息
 23 DESC emp;
 24
 25
 26 导入数据
 27 INSERT INTO emp VALUES(1001,'rose','analyst',15000,5000,null,'2010-2-2',10);
 28 INSERT INTO emp VALUES(1002,'tom','analyst',10000,3000,1001,'2010-3-5',10);
 29 INSERT INTO emp VALUES(1003,'jerry','analyst',10000,3000,null,'2010-3-5',10);
 30 INSERT INTO emp VALUES(1004,'smith','sales',8000,2000,null,'2010-5-5',10);
 31 INSERT INTO emp VALUES(1005,'blake','programmer',9000,null,null,'2010-10-7',30);
 32 INSERT INTO emp VALUES(1006,'zhangsan','sales',11000,null,null,'2009-12-15',30);
 33 INSERT INTO emp VALUES(1007,'lisi','clerk',2000,500,null,'2008-3-5',10);
 34 INSERT INTO emp VALUES(1008,'king','boss',20000,null,null,'2008-1-6',10);
 35 INSERT INTO emp VALUES(1009,'allen','clerk',8500,2000,null,'2009-3-5',30);
 36 INSERT INTO emp VALUES(1010,'dawson','sales',7400,3000,null,'2010-5-5',30);
 37
 38
 39 显示所有信息
 40 SELECT * FROM emp;
 41
 42
 43
 44
 45 1.查询2010年入职的员工（三种方法）
 46 方法一：
 47 SELECT
 48     ename,
 49     hiredate
 50 FROM
 51     emp
 52 WHERE
 53     hiredate LIKE '2010%';
 54
 55 方法二：
 56 SELECT
 57     ename,
 58     hiredate
 59 FROM
 60     emp
 61 WHERE
 62     YEAR(hiredate)=2010;
 63
 64 方法三：
 65 SELECT
 66     ename,
 67     hiredate
 68 FROM
 69     emp
 70 WHERE
 71     hiredate>='2010-01-01'  AND hiredate<='2010-12-31';
 72
 73
 74
 75 2.查询薪资在10000~20000之间的员工
 76 方法一：
 77 SELECT
 78     ename,
 79     salary
 80 FROM
 81     emp
 82 WHERE
 83     salary BETWEEN 10000 AND 20000;
 84
 85 方法二：
 86 SELECT
 87     ename,
 88     salary
 89 FROM
 90     emp
 91 WHERE
 92     salary >= '10000' AND salary <= '20000';
 93
 94
 95
 96 3。查询薪资不在10000~20000之间的员工
 97 方法一：
 98 SELECT
 99     ename,
100     salary
101 FROM
102     emp
103 WHERE
104     salary NOT BETWEEN 10000 AND 20000;
105
106 方法二：
107 SELECT
108     ename,
109     salary
110 FROM
111     emp
112 WHERE
113     NOT salary >= '10000' AND salary <= '20000';
114
115
116
117 4.查询姓名中含有a的名字的员工信息
118 SELECT
119     ename,
120     empno,
121     job,
122     hiredate
123 FROM
124     emp
125 WHERE
126     ename LIKE '%a%';
127
128
129
130 5.查询姓名中第二个字母含有a的员工信息
131 SELECT
132     ename,
133     empno,
134     job,
135     hiredate
136 FROM
137     emp
138 WHERE
139     ename LIKE '_a%';
140
141
142
143 6.查询所有员工的年薪是多少
144 SELECT
145     ename,
146     salary,
147     bonus,
148     salary * 12 + ifnull(bonus, 0) year_sal
149 FROM
150     emp;
151
152
153
154 7.显示所有员工的姓名,要求首字母大写(特殊难点)
155 -- 方法一:
156 SELECT
157     CONCAT(
158         upper(substr(ename, 1, 1)),
159         substr(ename, 2)
160     )
161 FROM
162     emp;
163
164 方法二:
165 SELECT
166     REPLACE (
167         ename,
168         substr(ename, 1, 1),
169         upper(substr(ename, 1, 1))
170     )
171 FROM
172     emp;
173
174
175
176 8.修改1002, 1003, 1004的领导为1001
177 UPDATE emp
178 SET mgr = 1001
179 WHERE
180     empno IN (1002, 1003, 1004);
181
182
183
184 9.修改1001, 1005的领导设置为1008
185 UPDATE emp
186     SET mgr = 1008
187 WHERE
188 --     empno IN (1001,1005);
189
190
191
192 10.修改表格名称, 将emp改为employee
193     alter table emp rename to employee;
194
195
196
197 11.修改1001, 1002 的入职时间为2019-07-30
198 UPDATE employee
199 SET hiredate = '2019-7-30'
200 WHERE
201     empno IN (1001, 1002);
202
203
204
205 12.修改1006, 1007的入职时间为2019-4-15
206 UPDATE employee
207 SET hiredate = '2019-4-15'
208 WHERE
209     empno IN (1006, 1007);
210
211
212
213 13.修改1002, 1007的入职时间为2020-8-26
214 UPDATE employee
215 SET hiredate = '2020-8-26'
216 WHERE
217     empno IN (1002, 1007);
218
219
220
221 14.查询今年入职的员工有哪些
222 SELECT
223     ename,
224     hiredate
225 FROM
226     employee
227 WHERE
228     YEAR (hiredate) = YEAR (CURDATE());
229
230
231
232 15.查询当月入职的员工有哪些
233 SELECT
234     ename,
235     hiredate
236 FROM
237     employee
238 WHERE
239     MONTH (hiredate) = MONTH (now());
240 AND YEAR (hiredate) = YEAR (curdate());
241
242
243
244 16.查询薪资大于10000且部门号为10的员工年薪
245 SELECT
246     ename,
247     salary,
248     bonus,
249     deptno,
250     salary * 12 + IFNULL(bonus, 0) year_sal
251 FROM
252     employee
253 WHERE
254     salary > 10000
255 AND deptno = 10;
256
257
258
259 17.查询薪资大于10000且奖金大于1000的员工信息
260 SELECT
261     *
262 FROM
263     employee
264 WHERE
265     salary > 10000
266 AND bonus > 1000;
267
268
269
270 18.查询当前员工中哪些员工已经超过了3年
271 SELECT
272     ename,hiredate
273 FROM
274     employee
275 WHERE
276     hiredate < DATE_SUB(CURDATE(), INTERVAL 3 YEAR);
277
278
279
280 -- 19.查询employee表所有数据
281 SELECT * from employee;

　　 -- 20.修改表格原先名称, 将employee改为emp
    alter table employee rename to emp;

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